# US 5,702,985 A · Hermetically sealed ceramic integrated circuit heat dissipating package fabrication method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,702,985 A - Document ID: US5702985A - Status: Granted - Kind: A - Application number: 08/325,719 - Filed: 1994-10-19 - Granted: 1997-12-30 - Earliest claimed: 1992-06-26 - Assignees: Staktek Corporation - Inventors: Carmen D. Burns - Web page: https://patentgrep.com/patent/US5702985A ## CPC - H10W 44/20: at high-frequency [HF] or radio frequency [RF] - H10W 40/10: Arrangements for heating - H10W 42/20: protecting against electromagnetic or particle radiation, e.g. light, X-rays, gamma-rays or electrons - H10W 42/25: against alpha rays, e.g. for outer space applications - H10W 70/415: {Leadframe inner leads serving as die pads} - H10W 70/421: {Shapes or dispositions} - H10W 70/65: Shapes or dispositions of interconnections - H10W 70/68: Shapes or dispositions thereof - H10W 76/12: characterised by their shape - H10W 76/157: having interconnections parallel to the insulating or insulated base - H10W 76/60: Seals - H10W 95/00: Packaging processes not covered by the other groups of this subclass - H10W 70/682: {comprising holes having chips therein} - H10W 72/5363: {the connected ends being wedge-shaped} - H10W 72/5449: {not being orthogonal to a side surface of the chip, e.g. fan-out arrangements} - H10W 72/5524: {comprising aluminium [Al]} - H10W 72/59: Bond pads specially adapted therefor - H10W 72/865: {Die-attach connectors and bond wires} - H10W 72/884: {Die-attach connectors and bond wires} - H10W 72/932: {Plan-view shape, i.e. in top view} - H10W 90/734: {between a chip and a stacked insulating package substrate, interposer or RDL} - H10W 90/754: {between a chip and a stacked insulating package substrate, interposer or RDL} - H10W 90/756: {between a chip and a stacked lead frame, conducting package substrate or heat sink} - Y10T 29/49121: Beam lead frame or beam lead device - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A method for achieving a hermetically sealed ceramic integrated circuit package having good thermal conductivity for efficiently transferring heat from an integrated circuit chip die contained therein. Use of an ultra-thin integrated circuit chip die, thin ceramic housing layers and external lead frame allow an ultra-thin overall package that may be used singularly or further densely packaged into a three dimensional multi-package array and still meet the critical performance and reliability requirements for both military and aerospace applications. ## Claims ### Claim 1 A method of manufacturing a hermetically sealed ceramic integrated circuit package having good thermal conductivity for efficiently transferring heat from an integrated circuit chip die contained therein, comprising the steps of: attaching at least one integrated circuit chip in a ceramic housing comprising a base, wire bond pads and seal ring, said integrated circuit chip having a face with circuit connection pads thereon and positioned wherein the face is accessible from within said ceramic housing; connecting said ceramic housing wire bond pads to said integrated circuit connection pads; attaching a cover to said ceramic housing seal ring wherein said cover and housing are hermetically sealed together; attaching a lead frame to said ceramic housing base, said lead frame having a plurality of electrical conductors that are fixedly aligned with said housing wire bond pads; and connecting said lead frame conductors to said housing wire bond pads. ### Claim 2 (depends on 1) The method of claim 1, wherein the step of attaching an integrated circuit chip in a ceramic housing comprises the step of firing silver loaded glass therebetween. ### Claim 3 (depends on 1) The method of claim 1, wherein the step of connecting said housing wire bond pads to said integrated circuit connection pads comprises the step of aluminum wedge bonding. ### Claim 4 (depends on 1) The method of claim 1, wherein the step of attaching a cover to said housing comprises the steps of: tinning the housing seal ring with solder; tinning the cover with solder; placing in a nitrogen filled oven said housing and said cover, said cover on top of and in communication with said housing seal ring; heating said housing solder tinned seal ring and cover until the solder melts; and cooling said housing and cover whereby a hermetic seal is formed therebetween. ### Claim 5 (depends on 1) The method of claim 1 after the step of connecting said housing wire bond pads to said integrated circuit connection pads, further comprising the step of attaching a thin polymer layer onto said integrated circuit chip face for alpha particle shielding. ### Claim 6 (depends on 1) The method of claim 1 after the step of connecting said lead frame, further comprising the step of attaching a thin insulating layer to the lead frame. ### Claim 7 (depends on 1) The method of claim 1 after the step of attaching a cover, further comprising the step of attaching a thin insulating layer over the cover and hermetic seal. ### Claim 8 A method of manufacturing a hermetically sealed ceramic integrated circuit package having a standard size and housing various sizes of integrated circuit chips with connections thereto made by means of a first lead frame laminated onto the face of the chip, the package having good thermal conductivity for efficiently transferring heat from the integrated circuit chip die contained therein, comprising the steps of: attaching at least one integrated circuit chip having an active face and having a first lead frame laminated to said active face in a ceramic housing comprising a base, bond pads and seal ring, said integrated circuit first lead frame having a plurality of conductors connected to connection pads of said integrated circuit chip and positioned wherein said first lead frame is accessible from within said ceramic housing; connecting said ceramic housing bond pads to said first lead frame conductors; and attaching a cover to said ceramic housing seal ring wherein said cover and housing are hermetically sealed together. ### Claim 9 (depends on 8) The method of claim 8, further comprising the steps of: attaching a second lead frame to an exterior major surface of said ceramic housing base, said second lead frame having a plurality of electrical conductors that are fixedly aligned with said housing bond pads; and connecting said second lead frame conductors to said housing wire bond pads. ### Claim 10 (depends on 1) The method of claim 1, wherein the step of attaching a cover to said housing comprises the step of welding said cover to said housing seal ring. ### Claim 11 (depends on 1) The method of claim 1, wherein the step of attaching a cover to said housing comprises the step of sealing with glass. ### Claim 12 (depends on 1) The method of claim 1, wherein the step of attaching an integrated circuit chip in a ceramic housing comprises the step of laminating a thermally filled polymer therebetween. ### Claim 13 (depends on 1) The method of claim 1, wherein the step of connecting includes thermal compression bonding. ### Claim 14 A method of manufacturing a lead frame on an integrated circuit package of a type having at least one substantially planar major exterior surface, said method comprising the steps of: mounting a lead frame comprised of a plurality of conductive elements formed in a substantially planar thermally conductive element to a first exterior major surface of an integrated circuit package, said package having a plurality of circuit conductors; and connecting selected ones of said lead frame conductors to selected ones of said integrated circuit package circuit conductors. ### Claim 15 (depends on 14) The method of claim 14, wherein the step of mounting said lead frame is with thermally conductive adhesive. ### Claim 16 (depends on 14) The method of claim 14, wherein the step of connecting selected ones of said lead frame conductors to selected ones of said integrated circuit package circuit conductors is by soldering. ### Claim 17 (depends on 14) The method of claim 14, wherein the step of connecting selected ones of said lead frame conductors to selected ones of said integrated circuit package conductors is by thermal compression bonding. ### Claim 18 (depends on 14) The method of claim 14, further comprising a step of covering said package with polymeric film. ### Claim 19 (depends on 14) The method of claim 14, further comprising a step of mounting a heat spreader in heat exchange relationship to said lead frame. ### Claim 20 (depends on 19) The method of claim 19, wherein said package has a first and a second major surface, said method further comprising the step of mounting a second heat spreader in heat exchange relationship to said second major surface of said integrated circuit package. ### Claim 21 (depends on 20) The method of claim 20, further comprising the step of mounting a second lead frame in heat exchange relationship to a second major surface of said second heat spreader. ### Claim 22 (depends on 21) The method of claim 21, further comprising the step of mounting a third heat spreader in heat exchange relationship to a second major surface of said second lead frame. ### Claim 23 (depends on 19) The method of claim 19, wherein said heat spreader comprises an electrically conductive ground plane adapted for connection to an electrical signal ground. ### Claim 24 (depends on 23) The method of claim 23, further comprising the step of providing holes in said ground plane to facilitate connection to selected ones of said lead frame conductors. ### Claim 25 (depends on 14) The method of claim 14, further comprising the step of mounting a heat spreader in heat exchange relationship to a second major surface of said integrated circuit package. ### Claim 26 (depends on 25) The method of claim 25, wherein said package has a first and a second major surface, said method further comprising the step of mounting a second lead frame comprised of a plurality of conductive elements formed in a substantially planar thermally conductive element in heat exchange relationship to said heat spreader. ### Claim 27 (depends on 25) The method of claim 25, wherein said heat spreader comprises an electrically conductive ground plane adapted for connection to an electrical signal ground. ### Claim 28 A method of manufacturing a lead frame on an integrated circuit package of a type having upper and lower substantially planar exterior major surfaces, said method comprising the steps of: mounting a first lead frame comprised of a plurality of conductive elements formed in a substantially planar thermally conductive element to said upper major surface of an integrated circuit package, said package having a plurality of circuit conductors; mounting a second lead frame comprised of a plurality of conductive elements formed in a substantially planar thermally conductive element to said lower exterior major surface of said integrated circuit package; and connecting selected ones of lead frame conductors of said first and second lead frames to selected ones of said integrated circuit package circuit conductors. ### Claim 29 (depends on 28) The method of claim 28, wherein the steps of mounting first and second lead frames to upper and lower major surfaces, respectively, of said integrated circuit package is with thermally conductive adhesive. ### Claim 30 (depends on 28) The method of claim 28, wherein the step of connecting selected ones of said lead frame conductors of said first and second lead frames to selected ones of said integrated circuit package circuit conductors is by soldering. ### Claim 31 (depends on 28) The method of claim 28, wherein the step of connecting selected ones of said lead frame conductors of said first and second lead frames to selected ones of said integrated circuit package circuit conductors is by thermal compression bonding. ### Claim 32 (depends on 28) The method of claim 28, further comprising the step of covering said package with polymeric film. ### Claim 33 (depends on 28) The method of claim 28, further comprising the step of mounting a first heat spreader in heat exchange relationship to said first lead frame. ### Claim 34 (depends on 33) The method of claim 33, wherein said first heat spreader comprises an electrically conductive ground plane adapted for connection to an electrical signal ground. ### Claim 35 (depends on 34) The method of claim 34, further comprising the step of providing holes in said ground plane to facilitate connection to selected ones of said first lead frame conductors. ### Claim 36 (depends on 28) The method of claim 28, further comprising the step of mounting a second heat spreader in heat exchange relationship to said second lead frame. ### Claim 37 (depends on 36) The method of claim 36, wherein said second heat spreader comprises an electrically conductive ground plane adapted for connection to an electrical signal ground. ### Claim 38 (depends on 37) The method of claim 37, further comprising the step of providing holes in said ground plane to facilitate connection to selected ones of said second lead frame conductors. ### Claim 39 (depends on 28) The method of claim 28, further comprising the step of mounting a first heat spreader in heat exchange relationship to said first lead frame and mounting a second heat spreader in heat exchange relationship to said second lead frame. ### Claim 40 (depends on 39) The method of claim 39, wherein said first heat spreader comprises an electrically conductive ground plane adapted for connection to an electrical signal ground. ### Claim 41 (depends on 40) The method of claim 40, further comprising the step of providing holes in said first ground plane to facilitate connection to selected ones of said first lead frame conductors. ### Claim 42 (depends on 39) The method of claim 39, wherein said second heat spreader comprises an electrically conductive ground plane adapted for connection to an electrical signal ground. ### Claim 43 (depends on 42) The method of claim 42, further comprising the step of providing holes in said second ground plane to facilitate connection to selected ones of said second lead frame conductors. ### Claim 44 (depends on 39) The method of claim 39, wherein said first and second heat spreaders comprise electrically conductive ground planes adapted for connection to an electrical signal ground. ### Claim 45 (depends on 44) The method of claim 44, further comprising the step of providing holes in said first and second ground planes to facilitate connection to selected ones of said first and second lead frame conductors. ### Claim 46 (depends on 44) The method of claim 44, further comprising the step of selecting the thickness of thermally conductive adhesive used to mount said electrically grounded first and second heat spreaders to obtain a controlled impedance stripline system. ### Claim 47 A method of manufacturing a lead frame on an integrated circuit package of a type having upper and lower substantially planar exterior major surfaces, said method comprising the steps of: mounting a heat spreader in heat exchange relationship to said upper major surface of an integrated circuit package, said package having a plurality of circuit conductors; mounting a lead frame comprised of a plurality of conductive elements formed in a substantially planar thermally conductive element to said upper major surface of said heat spreader; and connecting selected ones of said lead frame conductors to selected ones of said integrated circuit package circuit conductors. ### Claim 48 (depends on 47) The method of claim 47, further comprising the step of covering said package with polymeric film. ### Claim 49 (depends on 47) The method of claim 47, further comprising the step of mounting a second heat spreader in heat exchange relationship to said lower major surface of said integrated circuit package. ### Claim 50 (depends on 49) The method of claim 49, further comprising the step of mounting a second lead frame comprised of a plurality of conductive elements formed in a substantially planar thermally conductive element in heat exchange relationship to said second heat spreader. ### Claim 51 (depends on 47) The method of claim 47, further comprising the step of mounting a second heat spreader in heat exchange relationship to said said first lead frame. ### Claim 52 (depends on 51) The method of claim 51, further comprising the step of mounting a third heat spreader in heat exchange relationship to said lower major surface of said integrated circuit package. ### Claim 53 (depends on 51) The method of claim 51, further comprising the step of mounting a second lead frame comprised of a plurality of conductive elements formed in a substantially planar thermally conductive element in heat exchange relationship to said lower major surface of said integrated circuit package. ### Claim 54 (depends on 53) The method of claim 53, further comprising the step of mounting a third heat spreader in heat exchange relationship to said second lead frame. ### Claim 55 (depends on 52) The method of claim 52, further comprising the step of mounting a second lead frame in heat exchange relationship to a third heat spreader. ### Claim 56 (depends on 55) The method of claim 55, further comprising the step of mounting a fourth heat spreader in heat exchange relationship to a second lead frame.